It was the rarest of news in the coal mining hollows of Appalachia: A once powerful executive, Donald Blankenship, Wednesday to a year in prison for conspiring to violate federal mine safety laws at the Upper Big Branch mine in West Virginia, where 29 workers died in an explosion six years ago. The very idea that a dominant baron of the industry called King Coal could be brought to justice and put behind bars shook the region, where miners have long complained that they face dangerous and illegal working conditions that routinely result in no punishment.

Mr. Blankenship, who served as chief executive of the Company, was not accused of causing the explosion, but his management methods, so notoriously focused on profitability, came under investigation after the disaster and led to his federal conviction on a misdemeanor in a Charleston courthouse. While Mr. Blankenship sought probation and maintained his innocence at sentencing, Judge Irene Berger the maximum one-year sentence, citing “your part in a dangerous conspiracy” aimed at “putting profitability of the company ahead of the safety of your employees.”

The mine disaster, America’s worst in modern times, was traced to flammable coal dust and gas that accumulated despite workers’ complaints to management. The of thousands of violations was laid bare by investigators, with Mr. Blankenship maintaining that health and safety were uppermost concerns at the mine. Autopsies on the 29 victims told a different story of a hard work routine, with 71 percent showing signs of the incurable coal dust affliction called black lung — far above the industry average of 3.2 percent.

The mining executive was acquitted on felony charges, which involved accusations of securities fraud and making false statements and could have brought him decades in prison. Several of his lower-ranking supervisors were convicted earlier on felony charges for covering up hazardous conditions. Immediately after the disaster, there were assorted proposals for tougher federal mine and safety penalties, including upgrading the conspiracy violation to a felony with a longer sentence. But these have gone nowhere in the Republican Congress, compounding the tragedy of Upper Big Branch.

Mr. Blankenship was a hard-driving executive who demanded productivity reports every 30 minutes. He retired after the explosion with a $12 million golden parachute. “This game is about money,” he was heard emphasizing in one recorded comment uncovered in the investigation.

Judge Berger reminded the convicted coal baron that there was more than money at stake: “You, Mr. Blankenship, created a culture of noncompliance at Upper Big Branch where your subordinates accepted and, in fact, encouraged unsafe working conditions in order to reach profitability and production targets.”